A committee of Parliament in Ottawa has joined the Canadian campaign to save Enbridge Inc.’s 540,000 b/d Line 5 from threatened closure in Michigan.

“The Government of Canada may take legal action,” said a report released Thursday by the House of Commons Special Committee on the Economic Relationship Between Canada and the United States. The committee includes members of all political parties.

“Invoking the 1977 Transit Pipelines Treaty or the provisions of any other relevant international agreement, as well as filing an amicus curiae brief in U.S. federal court litigation, could assist in resolving the dispute,” the committee said.

Enbridge vice-president Vern Yu praised the Commons committee for encouraging government action. 

“The stakes could not be higher. Line 5 is not just a pipeline – it’s an economic lifeline in Canada and the United States,” said Yu.

Federal Natural Resources Minister Seamus O’Regan described keeping Line 5 open as a “non-negotiable” stand for the Canadian government during March committee hearings.

O’Regan has since repeated the message, adding that he delivered it to U.S. authorities including the White House. He has not disclosed actions that the Canadian government would take if Michigan fossil fuel foes succeed in shutting down Line 5.

The next public step in the dispute is a hearing May 12 in the U.S. District Court for the Western District of Michigan on a request by Governor Gretchen Whitmer for an order to close Line 5 at its Straits of Mackinac crossing between Lake Michigan and Lake Huron.

Whitmer and Michigan Attorney General Dana Nessel, who won a 2018 election with vows to shut Line 5, have lost state court battles for orders to stop its flows and cancel an agreement to bury the Straits pipe leg in a new $500-million utility tunnel.

Parallel to the Canadian save Line 5 campaign, a U.S. court-ordered effort to settle the dispute with confidential mediation was scheduled to start Friday.

Enbridge and Michigan’s executive branch agreed to comply with a direction by District Court Judge Janet Neff to try resolving their differences with help from a retired federal jurist, Gerald Rosen, serving as mediator.